. >> he takes legislation that kennedy introduced, that was stalled, really was not going to pass, civil rights, the tax cut bill, and, in an instant, johnson gets it moving towards passage. >> thank you very much. >> chris: last fall, he took part in a library of congress book festival, on the national mall. and it was clear he made johnson come alive for many readers. >> chris: do you like him? >> i don't like him or dislike him, you are in awe of him because you are constantly saying, look what he's doing now! >> chris: he got excited talking about johnson's rise to power. but, as we turn to the final book, he's writing now, about johnson's presidency and vietnam, his demeanor suddenly changed. >> the story is going to turn very dark as soon as vietnam enters the picture. it is sort of a tragic story. a story of his great dreams, that are destroyed by a war. >> chris: you are 76 now. do you ever worry that you are not going to have time to finish the last book? >> well, sure! but, you know, it is not productive to think like that. >> chris: how long do you think it will take you to fi